Polymeric crosslinkable compositions containing spiroorthocarbonates

ABSTRACT

Polymeric compositions containing spiroorthocarbonate groups and another functional group which reacts with hydroxyl groups are readily crosslinked on contact with water. These compositions are useful as sealants, coatings and encapsulants.

FIELD OF THE INVENTION

Polymeric compositions containing spiroorthocarbonate groups arecrosslinked by hydrolyzing the spiroorthocarbonate groups, and reactingthe hydroxyl groups that are formed to crosslink the composition.

TECHNICAL BACKGROUND

The crosslinking (curing) of polymers is an important commercialactivity, useful, for example, in elastomers, in coatings, and inthermoset materials such as are used for electronics. Controlling whenand under what conditions crosslinking takes place is usually criticalsince once a polymer is crosslinked it is usually not “workable”, thatis it may not be reshaped. In some applications, such as coatings andelectronic applications it may be desirable or even mandatory that nolower molecular weight compounds be volatilized during or after thecrosslinking of the polymers, so as not to contaminate sensitiveequipment such as electronics, and/or to pollute the environment, as inthe case of coatings.

Numerous ways have been found to avoid the production of volatilecompounds during curing. For example the reaction of epoxy groups withother groups such as hydroxyl groups may accomplish this result, but itis sometimes difficult to control after the ingredients are mixed and/orhigher temperatures are required. To avoid these types of problems,especially in coatings which often must be cured under conditions closeto ambient conditions and which often must be stable for long periodsbefore curing, other solutions have been found, such as the use ofspiroorthoesters, see for instance World Patent Application 9731073.However new and/or improved methods of crosslinking polymers are alwaysof interest.

For coatings, basecoat-clearcoat systems have found wide acceptance inthe past decade as automotive finishes. Continuing effort has beendirected to such coating systems to improve the overall appearance, theclarity of the topcoat, and the resistance to deterioration. Furthereffort has been directed to the development of coating compositionshaving low volatile organic content (VOC). A continuing need exists forcoating formulations which provide outstanding performancecharacteristics after application, and particularly mar-resistance andresistance to environmental etching. Heretofore, mar-resistant coatingswere attained by softening the coating, which depreciates otherperformance characteristics. The instant invention helps overcome thisproblem.

In repairing damage, such as dents to auto bodies, the original coatingin and around the damaged area is typically sanded or ground out bymechanical means. Some times the original coating is stripped off from aportion or off the entire auto body to expose the bare metal underneath.After repairing the damage, the repaired surface is coated, preferablywith low VOC coating compositions, typically in portable or permanentlow cost painting enclosures vented to atmosphere to remove the organicsolvents from the freshly applied paint coatings in environmentally safemanner. Typically, the drying and curing of the freshly applied painttakes place within these enclosures. Furthermore, the foregoing dryingand curing steps take place within the enclosure to also prevent the wetpaint from collecting dirt in the air or other contaminants.

As these paint enclosures take up significant floor space of typicalsmall auto body paint repair shops, these shops prefer to dry and curethese paints as fast as possible. More expensive enclosures arefrequently provided with heat sources, such as conventional heat lampslocated inside the enclosure to cure the freshly applied paint ataccelerated rates. Therefore, to provide more cost effective utilizationof shop floor space and to minimize fire hazards resulting from wetcoatings from solvent based coating compositions, there exists acontinuing need for low VOC fast curing coating formulations which cureunder ambient conditions while still providing outstanding performancecharacteristics, particularly overcoming mar problems and resistance toenvironmental etching.

Spiroorthocarbonates have been used in a variety of crosslinkablepolymeric systems, usually helping to crosslink the system by cationicpolymerization of the spiroorthocarbonate groups and sometimes(co)polymerizing other groups such as epoxides, see for instance WorldPatent Application 0040280, U.S. Pat. No. 5,808,108, and C. Pan, et al.,Polym. Int., Vol. 49, p. 74–80 (2000). None of these references describethe crosslinking of spiroorthocarbonate containing compositions viahydrolysis of the spiroorthocarbonate groups.

SUMMARY OF THE INVENTION

This invention concerns a first composition, comprising,

-   -   (a) (i) a first polymer having one or more intact        spiroorthocarbonate groups attached to a molecule of said first        polymer;    -   (ii) a crosslinking agent containing first functional groups        which react with hydroxyl groups, provided that said        crosslinking agent has an average of at least 2 first functional        groups per molecule of said crosslinking agent; and    -   (iii) optionally one or more of: one or more solvents; one or        more first catalysts for the reaction of said hydroxyl groups        with said first functional groups; and one or more second        catalysts for hydrolysis of said spiroorthocarbonate groups; or    -   (b) (i) a second polymer having second functional groups which        react with hydroxyl groups, provided that said second polymer        has an average of at least 2 second functional groups per        molecule of said second polymer;    -   (ii) a compound containing at least one intact        spiroorthocarbonate group; and    -   (iii) optionally one or more of: one or more solvents; one or        more first catalysts for the reaction of said hydroxyl groups        with said second functional groups; and one or more second        catalysts for hydrolysis of said spiroorthocarbonate groups.

Also disclosed herein is a second composition, comprising,

-   -   (a) (i) a first polymer having one or more intact        spiroorthocarbonate groups attached to a molecule of said first        polymer;    -   (ii) a crosslinking agent containing first functional groups        which react with hydroxyl groups, provided that said        crosslinking agent has an average of at least 2 first functional        groups per molecule of said crosslinking agent;    -   (iii) water; and    -   (iv) optionally one or more of one or more solvents; one or more        first catalysts for the reaction of said hydroxyl groups with        said first functional groups; and one or more second catalysts        for hydrolysis of said spiroorthocarbonate groups; or    -   (b) (i) a second polymer having second functional groups which        react with hydroxyl groups, provided that said second polymer        has an average of at least 2 second functional groups per        molecule of said second polymer,    -   (ii) a compound containing at least one intact        spiroorthocarbonate group;    -   (iii) water, and    -   (iv) optionally one or more of: one or more solvents; one or        more first catalysts for the reaction of said hydroxyl groups        with said second functional groups; and one or more second        catalysts for hydrolysis of said spiroorthocarbonate groups.

Also described herein is a first process for the crosslinking of apolymeric composition, comprising, exposing said polymeric compositionin the uncrosslinked form to water for a period of time to crosslinksaid polymeric composition, provided that said polymeric compositioncomprises

-   -   (a) (i) a first polymer having one or more intact        spiroorthocarbonate groups attached to said first polymer,    -   (ii) a crosslinking agent containing first functional groups        which react with hydroxyl groups, provided that said        crosslinking agent has an average of at least 2 first functional        groups per molecule of said crosslinking agent; and    -   (iii) optionally one or more of one or more solvents; one or        more catalysts for the reaction of said hydroxyl groups with        said first functional groups; and one or more catalysts for        hydrolysis of said spiroorthocarbonate groups; or    -   (b) (i) a second polymer having second functional groups which        react with hydroxyl groups, provided that said second polymer        has an average of at least 2 second functional groups per        molecule of said second polymer,    -   (ii) a compound containing at least one intact        spiroorthocarbonate group; and    -   (iii) optionally one or more of: one or more solvents; one or        more catalysts for the reaction of said hydroxyl groups with        said second functional groups; and one or more catalysts for        hydrolysis of said spiroorthocarbonate groups.

This invention also involves a second process for forming a crosslinkedcoating, comprising, applying a polymeric coating composition to asubstrate in an uncrosslinked form, exposing said polymeric coatingcomposition in an uncrosslinked form to water, and allowing saidpolymeric coating composition in an uncrosslinked form to crosslink,provided that said polymeric composition comprises

-   -   (a) (i) a first polymer having one or more intact        spiroorthocarbonate groups attached to said first polymer,    -   (ii) a crosslinking agent containing first functional groups        which react with hydroxyl groups, provided that said        crosslinking agent has an average of at least 2 first functional        groups per molecule of said crosslinking agent; and    -   (iii) optionally one or more of one or more solvents; one or        more catalysts for the reaction of said hydroxyl groups with        said first functional groups; and one or more catalysts for        hydrolysis of said spiroorthocarbonate groups; or    -   (b) (i) a second polymer having second functional groups which        react with hydroxyl groups, provided that said second polymer        has an average of at least 2 second functional groups per        molecule of said second polymer,    -   (ii) a compound containing at least one intact        spiroorthocarbonate group; and    -   (iii) optionally one or more of: one or more solvents; one or        more catalysts for the reaction of said hydroxyl groups with        said second functional groups; and one or more catalysts for        hydrolysis of said spiroorthocarbonate groups.

DETAILS OF THE INVENTION

By polymers herein are meant not only higher molecular weight polymers,with weight average molecular weights greater than 3000, but also lowermolecular weight polymers, sometimes called oligomers, with weightaverage molecular weights in the range, for example 300 to 3000.

By a spiroorthocarbonate group herein is meant a group of the formula

By an intact spiroorthocarbonate group is meant that the two rings ofthe spiro group are still present, at least before any desired reactionsuch as hydrolysis takes place.

A preferred compound containing a spiroorthocarbonate group is acompound of the formula

wherein R¹ and R² are hydrocarbylene or substituted hydrocarbylenebridging groups which have at least two bridging carbon atoms. It ispreferred that there independently be 2 or 3 atoms in each bridgebetween oxygen atoms in (I). By hydrocarbylene is meant an groupcontaining only carbon and hydrogen which has two free valences tocarbon atoms, and both free valences are not to the same carbon atom. Bysubstituted hydrocarbylene is meant one or more hydrogen atoms aresubstituted for by a functional group which does not interfere with thedesired reactions of, or the formation of, the compound involved.Suitable functional groups include halo, ether including alkoxy,hydroxyl, etc.

“Preferred groups for R¹ and R² each independently have theforumula—CR³R⁴—CR⁵R⁶—(CR⁷R⁸)_(n)— wherein n is 0 or 1, and each of R³,R⁴, R⁵, R⁶, R⁷ and R⁸ is hydrogen, hydrocarbyl or substitutedhydrocarbyl, provided that any two of R³, R⁴, R⁵, R⁶, R⁷ and R⁸ vicinalor geminal to each other taken togetber may form a ring. In onepreferred form R¹ and R² are the same. Independently preferred groupsfor R³, R⁴, R⁵, R⁶, R⁷ and R⁸ are hydrogen; alkyl, especially alkylcontaining 1 to 10 carbon atoms, more preferably methyl or ethyl; andhydroxyalkyl, especially hydroxymethyl. Substitution patterns forspecific preferred compounds (I) are given in Table 1.”

TABLE 1 R¹ R² Compound R³ R⁴ R⁵ R⁶ R⁷ R⁸ n R³ R⁴ R⁵ R⁶ R⁷ R⁸ n A CH₃ H HH H H 1 CH₃ H H H H H 1 B H H CH₂OH C₂H₅ H H 1 H H CH₂OH C₂H₅ H H 1 C HH H H — — 0 H H CH₂OH C₂H₅ H H 1 D H H H H H H 1 H H CH₂OH C₂H₅ H H 1 EH H H H H H 1 H H H H H H 1 F CH₃ H H H — — 0 CH₃ H H H — — 0 G H H H H— — 0 H H H H — — 0 H H H n-C₄H₉ C₂H₅ H H 1 H H n-C₄H₉ C₂H₅ H H 1 I H Hn- H — — 0 H H n- H — — 0 C₈H₁₇ C₈H₁₇The spiroorthocarbonates can be made by the reaction of an appropriatediol (not including for example any other hydroxyalkyl groups which mayalso be present in the “diol”) with a tetralkylorthocarbonate underreflux to remove byproduct alcohol derived from the alkyl group of thetetralkylorthocarbonate. If R¹ and R² are to be the same a single diolis used, while if R¹ and R² are different two different diols are used,and the product may be a mixture of 2 symmetrical spiroorthocarbonatesand one unsymmetrical orthocarbonate, and these threespiroorthocarbonates may be in equilibrium with each other. Forinstance, compound A is prepared from 1,3-butanediol, B fromtrimethylolpropane, C from trimethylolpropane and ethylene glycol, Dfrom trimethylolpropane and 1,3-propanediol, E from 1,3-propanediol, Ffrom 1,2-propanediol, g from ethylene glycol, H from 2,butyl-2-ethyl-1,3-propanediol, and I from 1,2-decanediol. Furtherdetails on synthesis of these compounds will be found in the Experimentsand U.S. Pat. Nos. 5,808,108 and 5,298,631; R. Bai, et al., GaofenziXuebao, p. 21–27 (1996); R. Bai, et al., Gongneng Gaofenzi Xuebao, vol.8, p. 321–327 (1995); Japanese Patent Application 60204789; all of whichare hereby included by reference.

In the crosslinkable compositions herein spiroorthocarbonate groups arepresent in some form (see below), and to initiate the crosslinkingreaction water comes in contact with these groups to hydrolyze them.This hydrolysis may be quite rapid, see for instance P. Deslongchamps,et al., Tetrahedron, vol. 56, p. 3533–3537 (2000). When aspiroorthocarbonate is simply hydrolyzed a “linear” carbonate linkage isformed, together with 2 hydroxyl groups, as illustrated below for thereaction of Compound E:

Note that in this reaction, no relatively volatile low molecular weightproducts are produced. Since these reactions may be acid catalyzed someof the ring opening of the spiroorthocarbonates may lead to cationicpolymerization rather than simple ring opening. Herein preferably themajor molar portion of the spiroorthocarbonates present, more preferablyat least about 75 mole percent, and especially preferably at least 90molar percent simply ring open and do not polymerize.

In the first and second compositions herein, and in the materials usedin the first and second processes, in (a)(i) and (b)(ii) thespiroorthocarbonate groups may be included by a variety of methods. Inone instance [in (b)(ii)] the spiroorthocarbonate may be included as a“monomeric” compound, such as compound E, which may hydrolyze, thusproviding reactive hydroxyl groups. Alternatively, thespiroorthocarbonate groups may be part of a (possibly low molecularweight) polymer [in (a)(i)]. For example a dihydroxyspiroorthocarbonate(which has not yet been hydrolyzed) such as Compound B may be reactedwith an excess of a diisocyanate such as bis(4-isocyanatophenyl)methane(MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HMDI) orisophorone diisocyanate (IPDI) to form an isocyanate ended “prepolymer”,which upon exposure to water undergoes hydrolysis of thespiroorthocarbonate forming hydroxyl groups, which react with theremaining isocyanate groups to crosslink the polymer. Sincespiroorthocarbonates often hydrolyze faster than isocyanate reacts withwater, this is believed to be main mode of the crosslinking reaction forthis type of polymer. Other diols such as ethylene glycol or1,4-butanediol may also be copolymerized into the (pre)polymer formed.It is noted that in this type of isocyanate containing (pre)polymer, thespiroorthocarbonate group is (at least before hydrolysis) part of themain chain (not on a branch) of the polymer formed.

However, the spiroorthocarbonate may also be present in the polymer aspart of a branch. For example, a monohydroxyl spiroorthocarbonate suchas Compound D may be converted to a (meth)acrylate ester byesterification and the resulting (meth)acrylic ester,

may be free radically copolymerized with other free radicallycopolymerizable monomers such as (meth)acrylates and styrenes. Analogousvariations will be obvious to the skilled artisan.

Also present in these compositions, as (a)(ii) or (b)(i), and theprocesses in which they are used is a material having a first or secondfunctional group which reacts with hydroxyl groups. This reaction shouldtake place under the conditions chosen for the crosslinking reaction.These conditions may be ambient conditions or heating or otherconditions that may be used to prod the reaction to proceed. Preferablythe reaction with hydroxyl groups should not produce any volatile lowmolecular weight compounds, except those normally found in air (CO₂,water, etc.) Typical groups which react with hydroxyl groups includeisocyanates (including isocyanurate trimers), epoxides, carboxylic acidanhydrides (especially those which are parts of polymers), melamine, andsilane(s). Isocyanates, melamine and silane are especially preferred forcoatings.

In (a)(i) the first polymer contains intact (before hydrolysis)spiroorthocarbonate groups, and a crosslinking agent contains firstfunctional groups which react with hydroxyl groups. The crosslinkingagent may be a monomeric compound such as a diisocyanate such as MDI,TDI, HMDI or IPDI, or an epoxy resin, or may be a polymer containingfirst functional groups. For example it may be (meth)acrylate copolymercontaining repeat units derived from 2-isocyanatoethyl (meth)acrylate orglycidyl (meth)acrylate. It is also possible that (a)(i) and (a)(ii) are“combined” in the same polymer, that is a single polymer acts as both(a)(i) and (a)(ii). For example one can copolymerize (II) with2-isocyanatoethyl (meth)acrylate or glycidyl (meth)acrylate andoptionally other copolymerizable monomers. When that single polymer isexposed to moisture presumably the spiroorthocarbonate groups willhydrolyze forming hydroxyl groups, which in turn will react with theisocyanate, carboxylic acid anhydride, melamine, silane(s) or epoxidegroups, whichever are present. This (a)(i) and (a)(ii) and may becombined as a single polymer or may be more than one substance.

In a similar manner, (b)(ii) may be a monomeric compound containing oneor more spiroorthocarbonate groups, more preferably onespiroorthocarbonate group.

In any of the compositions herein the polymeric materials may range fromrelatively low to relatively high molecular weight. It is preferred thatthey be of relatively low molecular weight so as to keep the viscosityof the compositions before crosslinking low, so as to avoid or minimizethe need for solvent(s).

The second composition herein contains water. It is to be understoodthat as the water contacts the spiroorthocarbonate groups present in thecomposition, the spiroorthocarbonate groups will start to hydrolyze,eventually leading to crosslinking of the composition. This is basicallywhat happens in the first and second process herein. The water may beintroduced in a variety of ways. For example, especially in the case ofa coating the water may introduced into the uncrosslinked orcrosslinking (while the crosslinking is taking place) coating byabsorption from the air. This is very convenient for making anuncrosslinked coating composition which is stable until exposed to(moist) air. Alternatively water may be mixed in a mixing head or spraymixing head (for a coating) just before crosslinking is to take place.This is particularly useful for making thicker crosslinked items such aselectronic encapsulants where diffusion of moisture into a thickersection will take longer. The introduction of water should be at a pointwhere the final shape of the polymeric crosslinked part can be formedbefore crosslinking takes place.

Other materials which may optionally be present in the compositions andprocesses include one or more solvents (and are meant to act only assolvents). These preferably do not contain groups such as hydroxyl orprimary or secondary amino which can react with either the first orsecond functional groups and/or spiroorthocarbonates. One or morecatalysts for the hydrolysis of spiroorthocarbonates may be present.These are typically Bronsted acids, but these acids should not be sostrong as cause substantial cationic ring opening polymerization of thespiroorthocarbonates and/or epoxides which may be present. Ifsubstantial cationic ring opening polymerization of spiroorthocarbonategroups takes place, this will often lead to premature crosslinking ofthe composition. The same caveats may be said for any catalysts whichmay be present which catalyze the reaction of hydroxyl groups with thefirst or second functional groups. What these catalysts may be willdepend on what the first or second functional group(s) present are. Suchcatalysts are known in the art, for example, for the isocyanate hydroxylreaction, a wide variety of catalyst can be used such as tin compounds,including dibutyltin dilaurate and tertiary amines such as triethylenediamine. These catalysts can be used alone or in conjunction withcarboxylic acids such as acetic acid.

The present compositions, and the process for making them crosslinked,are useful as encapsulants, sealants, and coatings. They are useful ascoatings, especially transportation (automotive) coatings and industrialcoatings. As transportation coating they are useful as both OEM(original equipment manufacturer) and automotive refinish coatings. Theymay also be used as primer coatings. They often cure under ambientconditions to tough hard coatings and may be used as one or both of theso-called base coat and clear coat automotive coatings. This makes themparticularly useful for repainting of transportation vehicles in thefield. An advantage of the present materials and processes inencapsulants and sealants is that when spiroorthocarbonates are used incrosslinking reactions the resulting product does not shrink or shrinkas much as usual in a typical crosslinking reaction. This means anyvolume to be filled by the crosslinked material will be more reliablyfilled with a lessened chance of voids being present due to shrinkageduring crosslinking.

For whatever uses they are put to, the compositions, and the materialsused in the processes described herein may contain other materials whichare conventionally used in such uses. For example, for use asencapsulants and sealants the composition may contain fillers, pigments,and/or antioxidants.

For coatings there may be a myriad of other ingredients present, some ofwhich are described below. In particular there may be other polymers(especially of low molecular weight, “functionalized oligomers”) whichare either inert or have functional group other than those that may actas (a)(ii) or (b)(i) or may act as (a)(ii) or (b)(i) and also react withother reactive materials in the coating composition.

Other additives also include polyaspartic esters, which are the reactionproduct of diamines, such as, isopherone diamine with dialkyl maleates,such as, diethyl maleate.

Representative of the functionalized oligomers that can be employed ascomponent i or ii are the following:

Acid Oligomers: The reaction product of multifunctional alcohols such aspentaerythritol, hexanediol, trimethylol propane, and the like, withcyclic monomeric anhydrides such as hexahydrophthalic anhydride,methylhexahydrophthalic anhydride, and the like.

Hydroxyl Oligomers: The above acid oligomers further reacted withmonofunctional epoxies such as butylene oxide, propylene oxide, and thelike.

Anhydride Oligomers: The above acid oligomers further reacted withketene.

Silane Oligomers: The above hydroxyl oligomers further reacted withisocyanato propyltrimethoxy silane.

Epoxy Oligomers: The diglycidyl ester of cyclohexane dicarboxylic acid,such as Araldite® CY-184 from Ciba Geigy, and cycloaliphatic epoxies,such as ERL®-4221, and the like from Union Carbide.

Isocyanate Oligomers: The isocyanurate trimer of hexamethylenediisocyanate, DESMODUR® 3300 from Bayer or Tolonate HDT® from Rhodia,Inc., and the isocyanurate trimer of isophorone diisocyanate, and thelike.

Aldimine Oligomers: The reaction product of isobutyraldehyde withdiamines such as isophorone diamine, and the like.

Ketimine Oligomers: The reaction product of methyl isobutyl ketone withdiamines such as isophorone diamine.

Melamine Oligomers: Commercially available melamines such as CYMEL® 1168from Cytec Industries, and the like.

AB-Funtionalized Oligomers: Acid/hydroxyl functional oligomers made byfurther reacting the above acid oligomers with 50%, based onequivalents, of monofunctional epoxy such as butylene oxide or blends ofthe hydroxyl and acid oligomers mentioned above or any other blenddepicted above.

CD-Functionalized Crosslinkers: Epoxy/hydroxyl functional crosslinkerssuch as the polyglycidyl ether of Sorbitol DCE-358® from Dixie Chemicalor blends of the hydroxyl oligomers and epoxy crosslinkers mentionedabove or any other blend as depicted above.

The compositions of this invention may additionally contain a binder ofa noncyclic oligomer, i.e., one that is linear or aromatic. Suchnoncyclic oligomers can include, for instance, succinic anhydride- orphthalic anhydride-derived moieties in the Acid Oligomers: such asdescribed above.

Preferred oligomers (i) have weight average molecular weight notexceeding about 3,000 with a polydispersity not exceeding about 1.5;more preferred oligomers have molecular weight not exceeding about 2,500and polydispersity not exceeding about 1.4; most preferred oligomershave molecular weight not exceeding about 2,200, and polydispersity notexceeding about 1.25. The compositions of this invention can comprise100% by weight of component (i) when (i) is a self-crosslinker. Moretypically, compositions will comprise 20–80 weight percent of (i),preferably 30 to 70 weight percent and more preferably 40 to 60 weightpercent, with the balance being (ii).

The coating compositions may be formulated into high solids coatingsystems dissolved in at least one solvent. The solvent is usuallyorganic. Preferred solvents include aromatic hydrocarbons such aspetroleum naphtha or xylenes; ketones such as methyl amyl ketone, methylisobutyl ketone, methyl ethyl ketone or acetone; esters such as butylacetate or hexyl acetate; and glycol ether esters such as propyleneglycol monomethyl ether acetate.

The coating compositions can also contain a binder of an acrylic polymerof weight average molecular weight greater than 3,000, or a conventionalpolyester such as SCD®-1040 from Etna Product Inc. for improvedappearance, sag resistance, flow and leveling and such. The acrylicpolymer can be composed of typical monomers such as acrylates,methacrylates, styrene and the like and functional monomers such ashydroxy ethyl acrylate, glycidyl methacrylate, or gammamethacrylylpropyl trimethoxysilane and the like.

The coating compositions can also contain a binder of a dispersedacrylic component which is a polymer particle dispersed in an organicmedia, which particle is stabilized by what is known as stericstabilization. Hereafter, the dispersed phase or particle, sheathed by asteric barrier, will be referred to as the “macromolecular polymer” or“core”. The stabilizer forming the steric barrier, attached to thiscore, will be referred to as the “macromonomer chains” or “arms”.

The dispersed polymer contains about 10 to 90%, preferably 50 to 80%, byweight, based on the weight of the dispersed polymer, of a highmolecular weight core having a weight average molecular weight of about50,000 to 500,000. The preferred average particle size is 0.1 to 0.5microns. The arms, attached to the core, make up about 10 to 90%,preferably 10 to 59%, by weight of the dispersed polymer, and have aweight average molecular weight of about 1,000 to 30,000, preferably1,000 to 10,000. The macromolecular core of the dispersed polymer iscomprised of polymerized acrylic monomer(s) optionally copolymerizedwith ethylenically unsaturated monomer(s). Suitable monomers includestyrene, alkyl acrylate or methacrylate, ethylenically unsaturatedmonocarboxylic acid, and/or silane-containing monomers. Such monomers asmethyl methacrylate contribute to a high Tg (glass transitiontemperature) dispersed polymer, whereas such “softening” monomers asbutyl acrylate or 2-ethylhexylacrylate contribute to a low Tg dispersedpolymer. Other optional monomers are hydroxyalkyl acrylates ormethacrylates or acrylonitrile. Optionally, the macromolecular core canbe crosslinked through the use of diacrylates or dimethacrylates such asallyl methacrylate or post reaction of hydroxyl moieties withpolyfunctional isocyanates. The macromonomer arms attached to the corecan contain polymerized monomers of alkyl methacrylate, alkyl acrylate,each having 1 to 12 carbon atoms in the alkyl group, as well as glycidylacrylate or glycidyl methacrylate or ethylenically unsaturatedmonocarboxylic acid for anchoring and/or crosslinking. Typically usefulhydroxy-containing monomers are hydroxy alkyl acrylates or methacrylatesas described above.

The coating compositions can also contain conventional additives such aspigments, stabilizers, rheology control agents, flow agents, tougheningagents and fillers. Such additional additives will, of course, depend onthe intended use of the coating composition. Fillers, pigments, andother additives that would adversely effect the clarity of the curedcoating will not be included if the composition is intended as a clearcoating.

The coating compositions are typically applied to a substrate by isconventional techniques such as spraying, electrostatic spraying, rollercoating, dipping or brushing. As mentioned above atmospheric moisturemay “diffuse” into the coating and cause curing, or alternatively justbefore the coating is applied it is mixed with an appropriate amount ofwater, as in a mixing spray head. Under these latter conditions it isimportant to apply the coating before it crosslinks. The presentformulations are particularly useful as a dear coating for outdoorarticles, such as automobile and other vehicle body parts. The substrateis generally prepared with a primer and or a color coat or other surfacepreparation prior to coating with the present compositions.

A layer of a coating composition is cured under ambient conditions inthe range of 30 minutes to 24 hours, preferably in the range of 30minutes to 3 hours to form a coating on the substrate having the desiredcoating properties. It is understood that the actual curing time dependsupon the thickness of the applied layer and on any additional mechanicalaids, such as, fans that assist in continuously flowing air over thecoated substrate to accelerate the cure rate. If desired, the cure ratemay be further accelerated by baking the coated substrate attemperatures generally in the range of from about 60° C. to 150° C. fora period of about 15 to 90 minutes. The foregoing baking step isparticularly useful under OEM (Original Equipment Manufacture)conditions.

In the Examples and Experiments, the following abbreviations are used:

-   -   RB—round-bottomed    -   RT—room temperature    -   THF—tetrahydrofuran    -   TLC—thin layer chromatography

Experiment 13.9-Diethyl-3.9-dihydroxymethyl-1,5,7,5,11-tetraoxaspiro[5,5]undecane

See also U.S. Pat. No. 5,808,108. To a one liter three neck RB flaskequipped with a Dean-Stark trap, a reflux condenser, stirrer and undernitrogen trimethylolpropane (65.10 g, 0.48 mol) and toluene (600 mL)were added. The solution was refluxed for one h during which 2×20 mLportions were collected in the Dean-Stark trap and discarded. Thesolution was cooled to RT and tetraethylorthocarbonate (46.7 g, 0.24mol) and 4-ethylbenzenesulfonic acid (0.3 g) were added. The resultingmixture was heated to reflux once again and the ethanol formed duringthe reaction was azeotropically removed. The azeotropic mixture wascollected in the Dean-Stark trap until the temperature reached 110° C.(boiling point of pure toluene). At this point about 210 mL of materialwas collected, which was shaken with brine. The toluene phase wasseparated giving ˜55 mL of ethanol. After the temperature reached 110°C. and the azeotropic mixture was collected the reaction was refluxedfor an additional h and then allowed to cool to RT. TLC (hexane/ethylacetate (1:3) showed the complete disappearance of the startingtrimethylolpropane and the appearance of the orthocarbonate.Triethylamine (3 mL) was then added to the cooled solution. The toluenewas removed at reduced pressure, resulting in a white solid material(crystallization may take up to two days). This material was dissolvedin diethyl ether and allowed to recrystallize affording 19.28 g ofmaterial (first crop) after drying under vacuum. The filtrate wasconcentrated and recrystallized from ether affording an additional 20.07g of material (second crop). ¹³C NMR (CDCl₃) (first crop): 6.10, 22.06,35.72, 61.08, 65.80, 66.30 and 113.80 (C_(orthocarbonate)).

Experiment 2 3,9-Dibutyl-3,9-Diethyl-1,5,7,11-tetraoxaspiro[5.5]undecane

See also U.S. Pat. No. 5,808,108. In a three neck 500 mL RB flaskequipped with a reflux condenser, a Dean-Stark trap and under nitrogen,2-butyl-2-ethyl-1,3-propanediol (35.33 g, 0.22 mol) and toluene (350 mL)were added. The resulting mixture was heated to reflux for 2 h. Theresulting solution was cooled to RT and 4-ethylbenzenesulfonic acid(0.35 g) and tetraethylorthocarbonate (21.3 g, 0.11 mol) were added. Thereaction mixture was heated to reflux and the azeotropic solutioncollected in the Dean-Stark trap. The azeotropic mixture was measuredand removed from the trap and poured into brine. The toluene phase wasseparated giving ˜22 mL of ethanol, via shaking with brine. TLC of thereaction mixture showed the complete conversion of the starting diol. Tothe cooled reaction mixture was added triethylamine (3.0 mL). Thereaction mixture was then concentrated at reduced pressure (rotovap) andthen dried under vacuum. This crude material was then fractionallyvacuum distilled and the fraction boiling at 175–181° C. at 240 Pa andcollected (24.72 g) as a water white clear liquid. ¹³C NMR (CDCl₃):4.59, 11.30, 20.72, 21.20, 22.29, 28.08, 31.78, 67.13, 112.20(C_(orthocarbonate)).

Experiment 3 2.8-Dimethyl -1,5,7,11-tetraoxaspiro[5.5]undecane

See also U.S. Pat. No. 5,808,108. In a 500 mL RB flask equipped with areflux condenser, a stirrer and a Dean Stark trap, 1,3-butanediol (20.0g, 0.22 mol), and toluene (350 mL) were added. After placing undernitrogen the resulting solution was heated to reflux for two h to removewater from the mixture. The solution was cooled to RT and4-ethylbenzenesulfonic acid (0.35 g) and tetraethylorthocarbonate (21.3g, 0.11 mol) were added. The solution was heated to reflux and theazeotropic mixture collected; The reaction was refluxed until thetemperature of the distillated reached 110° C. (boiling point of puretoluene). The collected azeotropic mixture was measured and weighed andthen poured into brine and the organic phase was separated, whichindicated ˜22 mL of ethanol was collected. TLC analysis indicated thatthe reaction was complete by the disappearance of the diol and theappearance of the product at R_(f)=0.59 (silica gel, EtOAc/hexanes(3/2). The reaction was cooled to RT and triethylamine (2.5 mL) added.The toluene was removed at reduced pressure (rotovap) and the resultingliquid dried under vacuum. Vacuum distillation afforded four fractionsof the desired product as a water white clear liquid boiling, bp: 70–75°C. at 40 Pa. Fractions 1 and 2 were slightly impure and were combined togive 5.715 g and fractions 3 and 4 were very pure and were combined togive 10.046 g. Overall yield: 15.761 g (75.66%). ¹³C NMR indicated theproduct to be a mixture of isomers.

Experiment 4 2,7-Dioctyl-1,4,6,9,-tetraoxaspiro[4,4]nonane

In a 500 mL RB flask equipped with a reflux condenser, a stirrer and aDean Stark trap were added 1,2-decanediol (38.48 g, 0.22 mol), andtoluene (350 mL). After placing under nitrogen the resulting solutionwas heated to reflux for two h to remove water from the mixture. Thesolution was cooled to RT and 4-ethylbenzenesulfonic acid (0.35 g) andtetraethylorthocarbonate (21.3 g, 0.11 mol). The solution was heated toreflux and the azeotropic mixture collected. The reaction was refluxeduntil the temperature of the distillated reached 110° C. (boiling pointof pure toluene). The collected azeotropic mixture was measured andweighed and then poured into brine, the organic phase was separate,which indicated ˜22 mL of ethanol was collected. The reaction was cooledto RT and triethylamine (2.5 mL) added. The toluene was removed atreduced pressure (rotovap) and the resulting liquid dried under vacuum.Vacuum distillation afforded the desired product as a water white clearliquid boiling at 195–197° C. at 240 Pa (25.44 g). ¹³C NMR indicated theproduct to be a mixture of isomers.

Experiment 5 N-Butyl Urethane of3.9-Diethyl3.9-dihydroxymethyl-1,5,7,11-tetraoxaspiro-[5,5]undecane

In a dry box, in an oven dried 300 mL RB flask equipped with a stirrer3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(28.827 g) and toluene (100 mL) were added. The solution was stirreduntil the orthocarbonate dissolved. n-Butyl isocyanate (20.852 g) anddibutyltin dilaurate (1.05 g) were added. A reflux condenser wasattached and the apparatus removed from the dry box where it wasimmediately placed under nitrogen and the resulting solution heated to70° C. for 4 h. The toluene was removed under vacuum to give a veryviscous material. ¹³C NMR of this straw colored material showed it tocontain some toluene together with the desired urethane. This materialwas dissolved in ethyl acetate and then column chromatographed [silicagel, hexanes ethyl acetate (1/1), column (35 cm×5 cm)], R_(f)=0.47. Thesolvent was removed at reduced pressure (rotovap and then dried undervacuum to give 38.88 g of a viscous material. NMRs (¹H and ¹³C) showedthe sample contained a small amount of ethyl acetate.

EXAMPLE 1 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added 1,4-diisocyanatobutane (0.72 g, 0.005 mol)followed by dibutyltin dilaurate (0.04 g). The resulting solution wasstirred for ˜5 min during which the ingredients became warm. To thissolution was added 4-ethylbenzenesulfonic acid (0.03 g). The resultingsolution was stoppered and removed from the dry box and then poured on aglass plate. After one h the coating was tacky and after 18 h a clearhard coating was obtained.

EXAMPLE 2 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added isophorone diisocyanate (1.11 g, 0.005 mol)followed by dibutyltin dilaurate (0.04 g). The resulting solution wasstirred for ˜5 min during which the ingredients became warm. To thissolution was added 4-ethylbenzenesulfonic acid (0.03 g). The resultingsolution was stoppered and removed from the dry box and then poured on aglass plate. After one h the coating was slightly tacky and after 18 h aclear hard coating was obtained.

EXAMPLE 3 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added isophorone diisocyanate (0.555 g, 0.0025 mol)followed by dibutyltin dilaurate (0.044 g). The resulting solution wasstirred for ˜10 min during which the ingredients became warm. To thissolution was added 1,4-diisocyanatobutane (0.368 g) followed by4-ethylbenzenesulfonic acid (0.046 g). The resulting solution wasstoppered and removed from the dry box and then poured on a glass plate.After 18 h a clear hard coating was obtained. Five days later, thePendulum Hardness Tester gave a Persoz hardness of 134.

EXAMPLE 4 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added isophorone diisocyanate (0.555 g, 0.0025 mol)followed by dibutyltin dilaurate (0.041 g). The resulting solution wasstirred for ˜10 min during which the ingredients became warm. To thissolution was added isophorone diisocyanate (0.555 g, 0.0025 mol)followed by 4-ethylbenzenesulfonic acid (0.03 g). The resulting solutionwas stoppered and removed from the dry box and then poured on a glassplate. After 18 h a clear hard coating was obtained. Five days later,the Pendulum Hardness Tester gave a Persoz hardness of 276. Attenuatedtotal reflectance (ATR) IR of the coating on the glass plate showed avery strong absorbance at 1696 cm⁻¹ indicating the presence of theurethane functionality.

EXAMPLE 5 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added isophorone diisocyanate (0.555 g, 0.0025 mol)followed by dibutyltin dilaurate (0.075 g). The resulting solution wasstirred for ˜10 min during which the ingredients became warm. To thissolution was added 1,4-diisocyanatobutane (0.72, 0.00519 mol),3,9-dibutyl-3,9-diethyl-1,5,7,11-tetraoxaspiro[5,5]undecane (0.845 g,0.00257 mol) followed by 4-ethylbenzenesulfonic acid (0.077 g). Theresulting solution was stoppered and removed from the dry box and thenpoured on a glass plate while retaining a small amount in the vial.After 18 h a clear hard coating was obtained. After two weeks thematerial in the stoppered vial was still a free flowing liquid with noapparent increase in viscosity. This demonstrates the pot life of theformulation in which it can be kept for a long time as long as moistureis excluded.

EXAMPLE 6 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added isophorone diisocyanate (0.555 g, 0.0025 mol)followed by dibutyltin dilaurate (0.075 g). The resulting solution wasstirred for ˜10 min during which the ingredients became warm. To thissolution was added isophorone diisocyanate (1.10 g, 0.005 mol)3,9-dibutyl-3,9-diethyl-1,5,7,11-tetraoxaspiro[5,5]undecane (0.845 g,0.00257 mol) followed by 4-ethylbenzenesulfonic acid (0.110 g). Theresulting solution was stoppered and removed from the dry box and thenpoured on a glass plate, except for a small amount retained in the vial.After 18 h a clear hard coating was obtained. After two weeks thematerial in the stoppered vial was still a free flowing liquid with noapparent increase in viscosity. This demonstrates the pot life of theformulation in which it can be kept unchanged as long as moisture isexcluded.

EXAMPLE 7 Coating Formulation

In a dry box, Desmodour® N3390 (1,6-diisocyanatohexane trimer fromBayer) (1.00 g), the n-butyl urethane of3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane (1.4g) and ethylbenzenesulfonic acid (0.06 g) were added at a vial and THF(˜1 mL) was then added to dissolved the mixture. After a homogeneoussolution formed the contents was poured on a glass plate and allowed tocure. After 24 h the resulting coating was a bit tacky to the touch.After 48 h a relatively hard coating resulted.

EXAMPLE 8 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added isophorone diisocyanate (0.555 g, 0.0025 mol)followed by dibutyltin dilaurate (0.075 g). The resulting solution wasstirred for ˜10 min during which the ingredients became warm. To thissolution was added isophorone diisocyanate (1.11 g, 0.005 mol)2,8-dimethyl1,5,7,11-tetraoxaspiro[5,5]undecane (0.483 g, 0.00257 mol)followed by 4-ethylbenzenesulfonic acid (0.07 g). The resulting solutionwas stoppered and removed from the dry box and then poured on a glassplate. After one h the coating was still tacky (almost wet) to thetouch. After 18 h a clear hard coating was obtained. Five days later,the Pendulum Hardness Tester gave a Persoz hardness of 104.

EXAMPLE 9 Coating Formulation

In a dry box,3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro[5,5]undecane(0.69 g, 0.0025 mol) was dissolved in THF (2.0 g) in a glass vial. Tothis solution was added isophorone diisocyanate (0.555 g, 0.0025 mol)followed by dibutyltin dilaurate (0.083 g). The resulting solution wasstirred for ˜10 min during which the ingredients became warm. To thissolution was added isophorone diisocyanate (1.11 g, 0.005 mol),2,7-dioctyl-1,4,6,9-tetraoxaspiro[4.4]nonane (0.914 g, 0.00257 mol)followed by 4-ethylbenzenesulfonic acid (0.084 g). The resultingsolution was stoppered and removed from the dry box and then poured on aglass plate. After one h the coating was still tacky (almost wet) to thetouch. After 18 h a clear hard coating was obtained. Five days later, aPendulum Hardness Tester gave a Persoz hardness of 162.

The coating was removed from the glass plate and a section placed ineach of the following solvents (˜10 mL): acetone, ethyl acetate, methylethyl ketone and toluene. Each mixture was shaken for 7 d. Upon removalthe coatings were intact and showed no swelling or discoloration, thusindicating that the coating was cross-linked.

EXAMPLE 10 Coating Formulation

The clearcoats were drawn down over electrocoated steel panels orthermoplastic olefin (TPO), using a 0.015 mm (6 mil) drawdown blade. Themicrohardness of the coatings was measured using a Fischerscope hardnesstester (model HM 100V, available from Fischer Technology, Inc., Windsor,Conn., USA). The tester was set for maximum force of 100 Nm ramped inseries of 50, 1 second steps. The hardness was recorded in N/mm². Theswell ratio of the free films (removed from TPO) was determined byswelling in methylene chloride. The free film was placed between twolayers of aluminum foil and using a LADD punch, a disc of about 3.5 mmdiameter was punched out of the film. The aluminum foil was removed fromeither side of the free film. Using a microscope with 10× magnificationand a filar lens the unswollen diameter (D_(o)) of the film measured.Four drops of methylene chloride were added to the film, the film wasallowed to swell for a few seconds and then a glass slide was placedover it The swell ratio was then calculated as: swellratio=(D_(s))²/(D_(o))².

In a glass jar 11.96 g of the product of Experiment 3 was combined with0.84 g of butyl acetate, 1.2 g of a 2% dibutyl tin dilaurate solution inethyl acetate, and 0.48 grams of a 10% BYK® 301 solution (flow additiveavailable from BYK-Chemie, Wallingford, Conn., in propylene glycolmonomethylether acetate). To this was added 19.58 g of Desmodur® BAZ4470 (IPDI isocyanurate trimer available from Bayer), 22.40 g ofDesmodur® 3300 (hexamethylene diisocyanate trimer available from Bayer)and 3.54 g of butyl acetate. This mixture was stirred and then 4.09 g ofa 40% solution of Nacure® XP-221 (a 70% solution of dodecylbenzenesulfonic acid in isopropanol, available from King Industries, Norwalk,Conn., USA) was added and the mixture was stirred. The mixture wasdrawndown to give coatings of ˜0.05 mm (˜2 mil) in thickness. After oneday the coating had a Persoz pendulum hardness of 237, a Fischerscopehardness of 95 N/mm², and a swell ratio of 2.16.

1. A composition, comprising, (a) (i) a first polymer having one or moreintact spiroorthocarbonate groups attached to a molecule of said firstpolymer each said intact spiroorthocabornate group having the generalformula,

wherein R¹ and R² are hydrocarbylene or substituted hydrocarbylenebridging groups having at least two bridging carbons and wherein R¹ andR² each independently have the formula,—CR³R⁴—CR⁵R⁶—(CR⁷R⁸)_(n)— wherein n is 0 or 1; and each of R³, R⁴, R⁵,R⁶, R⁷ and R⁸ independently is selected from the aroup consisting ofhydrogen, hydrocarbyl and substituted hydrocarbyl, provided that any twoof R³, R⁴, R⁵, R⁶, R⁷ and R⁸ vicinal or geminal to each other takentogether may from a ring wherein the spiroorthocarbonate groups arehydrolyzed with water to generate hydroxyl groups; and (ii) acrosslinking agent containing first functional groups selected from thegroup consisting of isocyanates, epoxide, carboxylic acid anhydrides,melamine and silanes which react with hydroxyl groups, provided thatsaid crosslinking agent has an average of at least 2 first functionalgroups per molecule of said crosslinking agent; and (iii) optionally oneor more of: one or more solvents; one or more first catalysts for thereaction of said hydroxyl groups with said first functional groups; andone or more second catalysts for hydrolysis of said spiroorthocarbonategroups; or (b) (i) a second polymer having second functional groupswhich react with hydroxyl groups selected from the group consisting ofisocyanates, epoxides, carboxylic acid anhydrides, melamine and silanes,provided that said second polymer has an average of at least 2 secondfunctional groups per molecule of said second polymer; (ii) a compoundcontaining at least one intact spiroorthocarbonate group each saidintact spiroorthocarbonate group having the general formula,

wherein R¹ and R² are hydrocarbylene or substituted hydrocarbylenebridging groups having at least two bridging carbons and wherein R¹ andR² each independently have the formula,—CR³R⁴—CR⁵R⁶—(CR⁷R⁸)_(n)— wherein n is 0 or 1; and each of R³, R⁴, R⁵,R⁶, R⁷ and R⁸ independently is selected from the group consisting ofhydrogen, hydrocarbyl and substituted hydrocarbyl, provided that any twoof R³, R⁴, R⁵, R⁶, R⁷ and R⁸ vicinal or geminal to each other takentogether may form a ring; and (iii) optionally one or more of: one ormore solvents; one or more first catalysts for the reaction of saidhydroxyl groups with said second functional groups; and one or moresecond catalysts for hydrolysis of said spiroorthocarbonate groups.
 2. Acomposition, comprising, (a) (i) a first polymer having one or moreintact spiroorthocarbonate groups attached to a molecule of said firstpolymer selected from the groups consisting of isocyanates epoxidescarboxylic acid anhydrides, melamine and silanes; (ii) a crosslinkingagent containing first functional groups which react with hydroxylgroups, provided that said crosslinking agent has an average of at least2 first functional groups per molecule of said crosslinking agent; (iii)water; and (iv) optionally one or more of: one or more solvents; one ormore first catalysts for the reaction of said hydroxyl groups with saidfirst functional groups; and one or more second catalysts for hydrolysisof said spiroorthocarbonate groups; or (b) (i) a second polymer havingsecond functional groups which react with hydroxyl groups, provided thatsaid second polymer has an average of at least 2 second functionalgroups per molecule of said second polymer; (ii) a compound containingat least one intact spiroorthocarbonate group; (iii) water; and (iv)optionally one or more of: one or more solvents; one or more firstcatalysts for the reaction of said hydroxyl groups with said secondfunctional groups; and one or more second catalysts for hydrolysis ofsaid spiroorthocarbonate groups.
 3. The composition as recited in claim1 which is reacted with water to form a crosslinked polymeric material.4. The composition as recited in claim 2 which is reacted with water toform a crosslinked polymeric material.
 5. The composition as recited inclaim 1 which is a coating composition.
 6. The composition as recited inclaim 2 which is a coating composition.
 7. The composition as recited inclaim 5 wherein the functional group which reacts with the hydroxylgroup is isocyanate.
 8. The composition as recited in claim 5 whereinthe second polymer is an oligomer.
 9. The composition as recited inclaim 8, wherein, the functional group which reacts with the hydroxylgroup is isocyanate.
 10. The composition as recited in claim 5 whereinthe composition further comprises pigments.
 11. A substrate coated witha coating composition as recited in claim
 5. 12. The composition recitedin claim 1 wherein R¹ and R² are the same.
 13. The composition recitedin claim 1 wherein each of R³, R⁴, R⁵, R⁶, R⁷ and R⁸ independently isselected from the group consisting of hydrogen, alkyl, and hydroxyalkyl.